*RPhoto can now be calculated based on maximum VPhoto value and maximum photo
current as 0.45V/1.5mA = 300 .
Based on above example and choice of RPhoto, if an average optical power of 0.5W is
desired, the typical VPhoto value will be IPhoto * RPhoto = 625 A * 300 = 187.5mV. As
such the APC reference threshold must be set to 187.5mV to allow the APC loop to
achieve and maintain 0.5W average optical power.